This step is for drums which use a balanced-action / spring-balanced mechanism to tension the head. Observing the MSR (Manufacturer’s Suggested Range), decide the lowest pitch and the highest pitch at which you want the instrument to sound. The lowest note chosen can also affect the available highest note on the drum and the efficiency of the balanced action mechanism, so please check the manual which came with your timpani for the suggested range for each drum. Sometimes it is beneficial to set the highest notes you will need on the drum and let the low notes fall where they may.
Some American models of timpani featuring the balanced action mechanism tend to have less range than many European models (often marketed for roughly an octave of usable range, depending on head type and setup). The overall range may be affected by the type of heads you are using. Some manufacturers’ heads can have a narrower range than other manufacturers’ heads, which may limit the usable range of the timpani suggested by the manufacturer. Please check the manual for any head specifications.
Sample MSR pitches for various timpani are:
32″ drum – D, 29″ drum – F, 26″ drum-B-flat, 23″ drum-D
Other Manufacturers Recommend 
(examples only). N.B. MSR conventions differ by manufacturer: some specify the MSR primarily by the lowest practical note, while others specify it by the highest practical note (or by a recommended span between them). Always follow your manufacturer’s manual.
The size of the head is determined by the counterhoop. Some timpani manufacturers use non-standard counterhoop sizes. Be sure to consult the owner’s manual for the correct size of heads needed for your instruments before ordering replacement heads.
Note for non-balanced-action drums: If your drums use a Dresden-style (clutch/ratchet) pedal system or another non-balanced mechanism, the idea of a usable range still applies, but the term MSR (and how the “range” is defined) may not. In that case, set your practical top and bottom notes based on the instrument’s response and your manufacturer’s guidance.